This laboratory is engaged in the following projects: 1. Nucleotide sequence analysis of DNA. We have determined the 3' terminal sequences of lambda and T7 DNA, and we are currently identifying these sequences on P2, 299, and 186 DNAs. Our objective is to find what features of these sequences are recognized by the enzyme which cleaves concatemers into mature molecules. We are also constructing a substrate from T7 restriction enzyme fragments which can be used to identify a similar sequence on T7 concatemers. 2. DNA replication in E. coli. We have found that KCN and CO inhibit E. Coli replication by causing rapid depletion of ATP and dNTPs. CO does not inhibit anaerobic cells, because these cells make ATP glycolytically. Surprisingly we found that uncouplers of oxidative phosphorylation inhibit replication in anaerobic cells as well as in tuluenized cells. We are studying the mechanism of this inhibition. 3. Kinetoplast DNA. Using electron microscopy, restriction enzyme analysis, and other enzymatic analyses, we are studying the structural organization of kinetoplast DNA from Leishmania tarentolae. These studies will form a basis for investigation of the replication and segregation of these enormous DNA networks.